TWiki on Clouds

'Clouds' are scalable and highly available computing resources, built using virtualization technologies, that can be used for web hosting or any other purpose, on a pay as you go basis. They are increasingly popular with startups as a way of delivering a service that can scale virtually without limit, and could be a way for independent TWikiHostingSites to compete with JotSpot, which is now hosted on Google's cloud. It is also an alternative to TWikiOnWebHostingSites.

Amazon EC2 is one of the best known cloud services, and enables any Xen based virtual machine to run - usually Linux. Since TWikiOnLinux is a proven approach, it should be very easy to get TWiki running on Amazon EC2 - for example, you could take their pre-built Ubuntu 7.10 server virtual machine, boot it up, install the Ubuntu apache2 and twiki (currently 4.1.2) packages, and you have a working EC2 TWiki service (see TWikiOnUbuntu for the details, it only takes one command line to install Apache and TWiki). There may be some other wrinkles, but it really should be that simple.

Another alternative is to use TWikiOnRedHat, perhaps using Red Hat's recently announced RHEL (enterprise Linux) cloud service, which is built on EC2.

Once you have got your TWiki configured correctly with required plugins, skins, etc, you could then clone it into new virtual machine instances (AMIs in EC2).

Some questions arising:

• How well does TWiki run using multiple servers for a single TWiki site?
  • Does the EC2 model work where you need shared state between servers? How would this work with TWiki?
  • I'm sure this has been discussed before, any links?
• What could you do with such a service?
• What are some of the limitations to be thought about?
  • For example, caching would remain important, but would it work across multiple servers?

-- Contributors: RichardDonkin - 06 Dec 2007

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